Two years ago, Thom Hunter, a volunteer coach at Central Mountain High School in Mill Hall, Pa., saw something special in a 15-year-old boy at the school: a remarkable natural running ability. “There’s not anyone tougher than him when he runs,” Hunter said of the teenager. “You see other people start out too hard like he does, and they just collapse. It’s amazing to watch him just push through it.” In Hunter, it seems, the young high school runner saw something that felt just as rare: a coach he could trust, an adult male who would neither abandon nor harm...